The present invention relates to an anchor. More particularly this invention concerns an anchor securable to the end of an anchor line, chain or cable to moor a floating boat or the like relative to the bottom.
An anchor normally comprises a shank having a ring end adopted to be attached to the anchor line, chain or cable, and a crown end from which projects a pair of arms formed with flukes. In the commonest type of fixed-fluke anchor there is also provided toward the ring end of the shank a stock which lies in a plane perpendicular to the plane of the flukes. The purpose of this stock is to position the anchor relative to the bottom so that one of its flukes will be pointed into the bottom. Thus when a pull is exerted on the anchor line this pointing-down fluke should dig into the bottom and the anchor should therefore grab. Frequently, particularly when the bottom is rocky or quite hard, it is necessary to drag such a fixed-fluke anchor a considerable distance before it finally digs in and grabs. Even then if the current or wind shifts considerably it is possible for the anchor line to swing around and even engage the upwardly directed fluke so as to pull the anchor free so that the boat will drift until the anchor graps again.
In another well-known type of anchor, known under the trade name as a "Danforth" anchor, the flukes are pivotal on the crown end of the shank. Thus these flukes can pivot from a central position lying in a plane including the shank to either of two extreme positions at an angle to this plane and pointing generally toward the ring end of the shank. Such an anchor is dropped in and lies flat on the bottom. When it is pulled along the bills of the flukes eventually dig into the bottom and seat the anchor securely. Such an anchor is efficient in relatively soft bottoms, but when the bottom is relatively hard such anchors normally skid along a considerable distance before grabbing.
In all of the known anchor types it is standard practice to use a 7:1 scope, that is to employ a length of anchor line equal to seven times the depth where the anchor is placed. Furthermore a standard such anchor weighing between 5kg and 25kg normally is only rated for a pulling load in the anchor line of between 80kg and 120kg.